Ultrahigh-Resolution Magnetic Resonance Mass Spectrometry Characterization of Asphaltenes Obtained in the Presence of Minerals

In this work, crude oil asphaltenes obtained using n-pentane in the presence of different minerals (sand and iron oxide) were analyzed using atmospheric pressure photoionization coupled to ultrahigh-resolution magnetic resonance mass spectrometry. Results indicate that these minerals induce a slightly larger amount of precipitated material than when n-pentane is used alone. The asphaltenes precipitated in the presence of the substrates also have higher hydrogen/carbon molar ratios. All detected classes showed lower average double bond equivalents independent of whether they become more or less abundant in the iron-oxide- or sand-precipitated asphaltenes. Additionally, there was an increase in some of the oxygen-containing species compared to the asphaltene precipitated using the standard method. This study gives additional evidence that the characteristics of asphaltene deposits are highly dependent upon the conditions and, in this case, the effect of inorganic material.